A shotgun shell, shotshell, or simply a shell is a self-contained cartridge loaded with shot or loaded with a slug. The shot is typically lead shot, but may be other materials including rubber for non-lethal projectiles.
Shotgun shells were first made of solid brass, then transitioned to paper and starting in the 1960s, shotgun shell casings again transitioned to plastic to replace paper casings. Paper and solid brass shells, while rarely used, are still made.
Today, shotgun shells are typically made having a proximal end, head or base covered in a thin brass covering. Shotgun shells having a more powerful propellant charge will often use “high brass” shells, with the brass extended up further along the sides of the plastic casing, while light loads will use “low brass” shells.
In modern shotgun shells, the distal end, or the launching end, of a shotgun shell is typically sealed by either roll crimping or star crimping the plastic casing. In roll crimping, the end wall of plastic casing is rolled down atop a closure wad. Star crimping involves inward crimping or bending the end walls of plastic casing forming a star-shaped seal at the launching end of the shotgun cartridge. Typically, a closure wad is not used in star crimping.